Compound documents may include color images, text, and graphics. Mixed raster content (MRC) is an International Telecommunication Union standard (ITU T.44 04/1999) that specifies a method for efficient representation of a compound document as a union of multiple layers. MRC also specifies methods for compressing the document using pre-determined encoders for the individual layers.
Although the ITU T.44 standard sets forth methods for efficient representation of the document once the layers are identified, the standard does not address decomposition of an MRC document into the individual layers. The decomposition approach, however, may have a significant influence on the compressibility of the resulting layers and thus the size of the compressed document. Thus although numerous distinct decompositions of the document may exist, they will not all yield the same level of compression. Trying each decomposition to identify the one with the optimal rate and quality is intractable.